The problem of studying the capabilities of a preliminary electromagnetic vision process is considered. A numerical approach is developed on the basis of three-dimensional electromagnetic scattering inversion. Computer simulations are performed by means of a numerical program implementing the moment method and making use of a pseudoinversion algorithm to overcome ill-conditioning problems. An investigation volume holding unknown dielectric objects is assumed to be the scene to be visioned. An observation domain is considered for which the electric field vector's components (amplitude and phase) to be measured are obtained via numerical simulations of the direct electromagnetic scattering problem. The effects of the geometrical configurations of the observation domain and the measurement errors are analyzed.